Usgs readings

[marcq]

Question about usgs stations and the reading you can get online. I understand the cfs and temp gage. My question is does Specific conductance, water, unfiltered, microsiemens per centimeter at 25 degrees Celsius. Mean and is there anyway to read clarity of a river based of these charts?

Thanks Marc

 

[afishinado]

marcq wrote:
Question about usgs stations and the reading you can get online. I understand the cfs and temp gage. My question is does Specific conductance, water, unfiltered, microsiemens per centimeter at 25 degrees Celsius. Mean and is there anyway to read clarity of a river based of these charts?

Thanks Marc

If there is a "turbidity" measurement at the gauge that would show clarity.

Few gauges offer turbidity measurements and unless you correlate what you observe to the reading, it really doesn't mean much.

 

[Tigereye]

Specific conductance, water, unfiltered, microsiemens per centimeter at 25 degrees Celsius

Without trying to get too "wonky" here, Microsiemens per centimeter is a measurement of the conductance of a solution, or how well it is able to conduct a current. The higher the number the more conductive it is.

Water's conductivity is proportional to the amount of dissolved solids in the water. A glass of salt water is more conductive than a glass of deionized water. The salt (Sodium Chloride) is dissociated into the charged ions Sodium+ and Chloride-. These ions are what allow the the current to pass through, the more ions the easier it is to pass thru or conduct.

The "unfiltered per centimeter at 25C" is just a way of stating the standard conditions in which the test was performed, so you are comparing apples to apples.

Generally speaking high conductivity could be an indicator of pollution ie road salt, acid rain, phosphates etc.

Limestones streams have high conductivity due to the dissolved calcium present.

The number needs to be taken into context with other factors to make a determinations as to water quality.